Field of the Invention
The present invention relates to a die-casting piston, comprising a receiving unit attachable to a piston rod.
Description of the Background Art
A die-casting piston having a hollow cylindrical sliding body, which is disposed on the lateral surface of a base body, is known from the publication DE 100 40 578 C1. A die-casting piston of this type is characterized in that the hollow cylindrical sliding body is spread apart, so that it is always in contact by its outer surface with the inner wall of the filling chamber surrounding it. This ensures that the sliding body of the piston rests tightly against the inner wall of the filling chamber everywhere, so that no air is able to flow into the filling chamber and thus into the die-casting chambers of a die-casting machine. To form a better seal, the sliding body is expandable radially only to a limited extent. Worn parts, in particular the sliding body, are replaced by breaking down the piston into its individual parts. For this purpose, the piston must be removed from the piston rod.
A plunger piston for cold chamber die casting machines is also known from the publication DE 199 38 076 A1, which comprises a piston head and a piston rod fixedly connected thereto. As part of the piston head, a sleeve extending up to the piston rod is designed in such a way that a cooling system having a plurality of cooling channels is formed between the sleeve and the interior of the piston head. On the front end, a planar head plate is disposed on the sleeve, which is fixed on the front end of the piston head from the front with the aid of screws. The head plate planarly abuts the front end of the sleeve, whereby the front end of the plunger piston also forms a counter-bearing for absorbing the forces during the plunging action.
A die-casting piston is also known from the publication EP 2 862 647 A1, which is incorporated herein by reference, which includes a base body attachable to a piston rod and having a melt-side end face, on whose lateral surface at least one hollow cylindrical sliding body is mountable, and a closed end ring is situated between the end face of the base body and the end face of the sliding ring. The end ring is attachable to the base body with the aid of a connecting device. The closed end ring is axially mountable on the lateral face of the base body over the end face of the base body, where it may be locked and released again with the aid of the connecting device. The closed end ring is furthermore used as a front-end first holding element for the hollow cylindrical sliding body. Due to this structural approach, wearing parts may be replaced from the front, i.e. from the piston front end. For this purpose, slide bushes, expansion rings and scraper rings are pushed over the piston head and secured with the end ring as the first holding element.
A multipart die-casting piston is also disclosed in DE 10 2005 048 717 A1 for fastening to an end area of a piston rod on the high-pressure side, which is axially displaceable in a casting cylinder of a cold chamber die-casting machine. The piston comprises a piston cover on the high-pressure side, which has a piston end wall, and a piston body in the form of a bush, which abuts the piston cover on a low-pressure side. The piston body is connected to the piston cover with the aid of fastening screws, forming a structural unit. Bayonet locking members assigned to each other on the piston cover and the end area are proposed for axially fixing the piston to the end area of the piston rod. Locking mechanisms situated in the piston cover may make it difficult to cool the piston on the front end, particularly in the location to which heat is applied the most during operation, due to their structural design having material projections.